Winery Wastewater Treatment Using Flat Panel Airlift Photo-bioreactor with a Mixture of Algae and Bacteria
ABSTRACT
Airlift reactors are pneumatically agitated reactors with circulation in a defined cyclic pattern through a loop of conduits. The possibility of providing the required aeration and agitation during growth processes, with low energy input is a major reason for interest in airlift reactors. Although many photo-bioreactors have been reported widely in the literature, few flat panel airlift photo-bioreactors have been used, especially with applications for winery wastewater treatment. Winery wastewaters are characterized by large seasonal fluctuations in volume and composition and are often discarded with little or no treatment. In winery wastewater flat panel airlift photo-bioreactors, bacteria numbers decrease considerably in the case of raised algae concentrations in the effluent. Simultaneously, algae remove nutrients from the winery wastewater for the formation of biomass. However, suspended algae also cause a high secondary pollution in the effluent of winery wastewater treatment. It is proposed that the naturally occurring bacteria and algae be adsorbed onto inert carriers such as polyethylene beads to form biofilm and also reduce the chemical oxygen demand (COD) of winery wastewater. The problem of separation of algae and water can be avoided. In this study the possibilities for bacteria reduction and COD removal were examined with the aid of an algal biofilm onto polyurethane particles with a flat panel airlift photo-bioreactor. The results show that an algal biofilm process can be used for treating winery wastewater. The bacteria and algae could therefore play an important role in the degradation of organic compounds under aerobic conditions, such as those associated with a flat panel airlift photo-bioreactors.